This invention relates to defoaming of aqueous systems. In particular, the invention provides a hydrophobic solid that does not require intensive treatment to disperse it in a water insoluble liquid for use.
Defoamers for aqueous systems often consist of hydrophobic particles dispersed in a hydrophobic liquid. The hydrophobic particles are prepared by coating a generally hydrophilic material with a silane or silicone oil and curing in the required manner. Hydrophilic particles such as silica and alumino silicate have proved successful base materials for use in these systems. To complete preparation of the defoamer, the hydrophobic particles are dispersed in a water insoluble organic liquid such as a mineral oil by ball milling or other intensive methods. U.S. Pat. Nos. 3,408,306 and 4,008,173 disclose defoaming compositions and the methods by which such materials are prepared and used.
It is an object of this invention to provide a new base for the preparation of defoamers. It is also an object of this invention to provide a method for preparing defoamers that does not require intensive mixing or milling.